Hypoparathyroidism in a Child with MELAS Syndrome: A Case Report of Severe Lactic Acidosis and Symmetrical Bilateral Basal Ganglia Calcification.

Introduction: MELAS syndrome is a mitochondrial disorder typically characterized by brain dysfunction and endocrinopathies, but it rarely presents with hypoparathyroidism (HP). Case Presentation: Here, we report the case of a child who initially presented with vomiting and convulsions. Blood gas analysis revealed significant hyperlactatemia and hypocalcemia. The child's urinary calcium level was markedly decreased, measured at 0.15 mmol/24h, well below the normal range. A brain CT scan showed symmetrical calcification in the bilateral basal ganglia. Endocrine testing confirmed low parathyroid hormone (PTH) levels. During hospitalization, the child received treatment for recurrent seizures, including midazolam and levetiracetam. One month post-discharge, the child was readmitted due to elevated lactate levels. Genetic testing confirmed the diagnosis of MELAS syndrome, identifying the m.3243A > G mutation in the MT-TL1 gene. Under symptomatic treatment, the child has not experienced any further convulsions and has been regularly followed up at our hospital. Conclusions: This case underscores the importance of considering MELAS syndrome in patients presenting with hypoparathyroidism. Effective management of epileptic seizures and maintaining an appropriate calcium-to-phosphorus balance are crucial for minimizing brain damage and improving the patient's prognosis.